Polytrimethylene ether glycol (“PO3G”) and its use have been described in a number of patents and patent applications. PO3G can be prepared by dehydration of 1,3-propanediol or by ring opening polymerization of oxetane. PO3G can be prepared from 1,3-propanediol, preferably as described in U.S. Published Patent Application Nos. 2002/7043 A1 and 2002/10374 A1, both of which are incorporated herein by reference.
U.S. Published Patent Application No. 2002/7043 A1 teaches that the reaction mixture can comprise up to 50 mole %, preferably 1 to 20 mole %, based on all diols present, of a comonomer diol other than oligomers of 1,3-propanediol. Listed are 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol and mixtures thereof. More preferred as comonomers are 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 2,2-diethyl-1,3-propanediol.
Similarly, U.S. Published Patent Application No. 2002/10374 A1 teaches that the reaction mixture can comprise up to 50 mole %, preferably 1 to 20 mole %, based on all diols present, of a comonomer diol other than oligomers of 1,3-propanediol. Listed are aliphatic diols, for example 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 3,3,4,4,5,5-hexafluoro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexadecafluoro-1,12-dodecanediol, cycloaliphatic diols, for example 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and isosorbide, polyhydroxy compounds, for example glycerol, trimethylolpropane, and pentaerythritol. A preferred group of comonomer diol is selected from the group consisting of 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, isosorbide, and mixtures thereof.
Polyether ester elastomer comprising polytrimethylene ether ester soft segment and tetramethylene and trimethylene ester hard segments are described in U.S. Pat. No. 6,562,457 B1 and U.S. Published Patent Application No. 2003/120026 A1, both of which are incorporated herein by reference. Polytrimethylene ether ester amides are described in U.S. Pat. No. 6,590,065 B1, which is incorporated herein by reference. Polyurethanes and polyurethane ureas are described in U.S. patent application Ser. No. 10/215,575, filed Aug. 9, 2002 (published as US 2004-0030060 A1), which is incorporated herein by reference.
Polytrimethylene ether glycol is preferably prepared by polycondensation of 1,3-propanediol, preferably using an acid catalyst as described in U.S. Published Patent Application Nos. 2002/7043 A1 and 2002/10374 A1. Polyethylene glycol, on the other hand, is made from the ring-opening polymerization of ethylene oxide, and can not be polymerized from ethylene glycol by acid catalyzed polycondensation due to the cyclization of its dimer into dioxane.